A standard rotary impact breaker or crusher has a housing forming a breaker surface and a rotor that rotates about an axis in the housing and that is provided with a plurality of impact elements that strike the material to be comminuted to break it directly, throw it against a breaker surface, or crush it. Typically the rotor is generally cylindrical and the impact elements are bolted radially to its outer surface.
Such an apparatus is used to comminute bulky hard items such as building debris, slag, smelting residue, and the like. Thus the impact element are subjected to enormous stresses which can break them and/or break the bolts securing them to the rotor. When damaged it is fairly common for the element to fly off the rotor, leaving the surface it was mounted on exposed and subject to damage by the normally rough and hard material being comminuted.
When an element-mounting surface of a rotor is damaged it is necessary to remove the entire rotor from the machine so that the damaged surface can be machined and refinished. This is clearly a very onerous job entailing substantial down time.